It is proposed to investigate the mechanism of DNA transport and integration in the transformable B. subtilis, 168 strain. Mutants blocked in different stages of transformation and transfection will be isolated, and characterized genetically. Temperature-sensitive mutants will be examined for structural changes in membrane components and the nature of membrane proteins with affinities for donor DNA molecules studied. The fate of donor DNA will be followed in these mutants. Exodeoxyribonuclease and endodeoxyribonuclease activities associated with purified competent cells will be investigated, and the enzymes purified. Mutants with enhanced competence will also be isolated and investigated to determine the nature of competence restriction.